As is known, when washing textiles, fabric softener is used in the final wash. This reduces hardening of the fabric, which is caused by drying. The handle of the textiles treated in this way, such as hand and bath towels and also underwear and bed linen is favorably influenced.
The fabric softeners which are usually used are cationic compounds, for example quaternary ammonium compounds, which, as well as long-chain alkyl radicals, may also contain ester or amide groups, for example as described in U.S. Pat. Nos. 3,349,033, 3,644,203, 3,946,115, 3,997,453, 4,073,735 and 4,119,545. These components are added to the rinsing bath on their own or in mixtures with other cation-active or else neutral substances in the form of aqueous dispersions.
Frequent use is made of ammonium compounds which contain ester bonds, as described, for example, in EP-A-O-,239,910, and U.S. Pat. Nos. 3,915,867, 4,137,180 and 4,830,771.
Ester compounds based on triethanolamine, such as N-methyl, N,N-bis(beta-C.sub.14-18 -acyloxyethyl), N-betahydroxyethyl-ammonium methosulfate, which are marketed under tradenames such as TETRANYL.RTM. AT 75 (trademark of KAO Corp.), STEPANTEX.RTM. VRH 90 (trademark of Stepan Corp.) or REWOQUAT.RTM. WE 18 (trademark of Witco Surfactants GmbH) are particularly widespread.
Although these cationic compounds are effective softeners when used in the final rinsing bath, they do have certain disadvantages when used.
One of the disadvantages of such compositions is that the required high level of simultaneously good rewetting power and soft handle of the textiles treated therewith is still not satisfactory.
Rewetting power is taken to mean, in general, the absorption of liquid by the fibers. Insufficient rewetting power is, however, disadvantageous where relatively large amounts of liquid are to be absorbed from the surface of the skin, e.g. with hand and bath towels and underwear and bed linen.
Using processes known per se (batch or continuous processes), it is possible to prepare stable fabric softener dispersions using these products.